Abstract: In shallow water, there are high-level clutters in the reverberation which are caused by large scale scatters such as rocks. The clutters can lead to false alarms and decrease the detection performance. Reasonable waveform design may effectively suppress the clutters. Even though using Doppler sensitive waveform or decreasing waveform Doppler tolerance have been proved effective on suppressing clutters, the evaluation and quantification on clutter suppressing capacity of waveform is essential for waveform adjustment and design. There has no exact evaluation method on waveform clutter suppressing ability now. Firstly, this paper declares the principle of waveform suppressing clutter through modeling. Then, aiming at the performance evaluation problem of waveform suppressing clutters, we propose a method by adopting mixture statistical model to fit the reverberation envelope and estimate the clutter proportion. Finally, the proposed method is verified by lake experiments. The proposed method estimates the performance through the variation of statistical characteristics of reverberation. It contributes significant information to the waveform selection and parameter design.